We all know about the employee-of-the-month and the bunny-of-the-month. I just learned of a new one: the molecule-of-the-month. Check out this month’s centerfold at the RCSB Protean Data Bank.
One of the reasons Charles Darwin could propose his theory of evolution by mutation and natural selection as the explanation for the diversity of life was the assumption that less complex organisms were first, and that less complex means simpler. This suggests the tree of life, i.e., that simpler organisms are the ancestors of multiple more complex organisms, forever branching until we reach the most complex varieties of today. This train of thought was logical 150 years ago, because the cell was thought to be “simply” a blob of goo held together by a thin skin. Since one bag of goo seemed pretty much like another, new arrangements of the same goo bags could yield different animals. Right?
The one thing that has for sure evolved is our understanding of the goo. Today we estimate that the human body contains about 100,000 different molecules in its cells, and none of them are what we might call “simple.” As a matter of fact, the simplest of all viruses, are not simple either. Each one is a tiny machine part or tool with a specific function. That function is not only facilitated by the shape and size of the molecule, but also by the strength and positive and negative charges distributed about the molecule.
Today there seems to be no shortage of new discoveries of the complexity of life-related molecules, as evidenced by two molecules being featured for May, 2010, the month of this post. One is a virus that causes distemper in cats, parvoviruses; and the other is a repair molecule in humans, Mre11 Nuclease. The parvovirus neutralizes one cell in cats. With two modifications it can neutralize the same cell in dogs. Mre11 nuclease prevents mutation by repairing the ends of broked DNA strands. Both are pretty specific in function.
No life is made of goo. No life is simple. No explanation for it can be either.
“No explanation for it can be either.”
Evolution over 4 billion years is not a “simple” explanation. But it is obviously correct.